Part of a field glass



FIG. 1 is a left side elevational view of a part of a field glass showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a front perspective view thereof, the opposed interior elevations are not part of the claimed design;

FIG. 4 is a front elevational thereof;

FIG. 5 is a bottom plan view thereof;

FIG. 6 is a top plan view thereof; and,

FIG. 7 is a back elevational view thereof.

The broken lines form no part of the claimed design. 

The ornamental design for a part of a field glass, as shown and described. 